Birth and development

Fertilization- Only one sperm fertilizes the egg. In the first week the egg undergoes many cell divisions and travels to the uterus.

Zygote- United sperm and egg

Cell division- From the two cell stage till about nine weeks the growing structure is called an embryo.

Beginning of life cycle

The Blastocyst- 5 days after fertilization the embryo reaches the uterus where it floats free for a few days. At this time made up of 50-100 cells. The structure is now called a blastocyst and is a sphere of cells surrounding a hallow center.

Implantation- The blastocyst begins to attach itself to the wall of the uterus.

Amniotic Sac- Surrounds the embryo and is filled with amniotic fluid.

Placenta- Attachment holding the embryo to the wall of the uterus. Oxygen, nutrients and blood pass through to the embryo through the placenta. Harmful things can pass too..Like?

Umbilical cord- 25 days after fertilization this rope like cord develops between the embryo and placenta.

Development in the uterus

During the first 2 months of development major body systems and organs start to form.

By the end of 8 weeks the embryo is about an inch long and has recognizable external features(eyes, nose, limbs ect)

The thrid month until birth the developing human is called a fetus.

Development

During this time the fetus kicks and moves which shows muscle development.

As the nervous system develops, the fetus becomes sensitive to light, sounds, and alternates periods of activity with periods of sleep

7-9 months the fetus grows in proportion to the size of the head. At 9 months the fetus is born.

Fetus

Zygote- Sperm fertilizes egg

Embryo- From 2 cell stage until 9 weeks

Fetus- Three months until birth

Stages

Labor: 2-24 hrs or longer. Strong contractions of the muscles of the uterus cause the cervix to dilate.

Each contraction lasts approximately 30-90 seconds. At first they may be minutes apart but are usually only a few seconds apart at the end of the birth process.

Amniotic sac breaks and cervix becomes softer and wider.

The Birth Process

Delivery of the baby: Takes 30 mins- over 2 hrs.

Contractions of the uterus continue and the baby is pushed out, usually head first, through the cervix and vagina.

Doctor will then clamp and cut the umbilical cord, which has no nerve endings.

Nose and mouth are suctioned Eye drops added to prevent infection An injection of vitamin K to prevent excess

bleeding from umbilical cord Heel is pricked to check blood for protein

levels

Delivery of after birth: Contractions of the uterus push out the placenta.

This stage takes typically 15-30 mins

This is the 6 week period of adjustment for the parents and new born.

Circulatory system and heart under go changes that send more blood to the lungs, because the baby now gets its oxygen there.

Nervous system reacts to sensations. The new born is learning to build a close

bond with its mother and father and is learning to get what it needs for survival.

Postpartum Period

Mother: Changing hormone levels tell the body to produce milk and cause the uterus to gradually shrink to normal size.

Mother may feel overwhelmed or very sad. If this depression lasts longer or causes the

mother to withdraw from the baby or people, she should seek prompt medical help.

This means she could have postpartum depression.

Cesarean Section- A surgical method of birth. Done when a mothers hips are too narrow or illness or other conditions are present.

Stillbirth- Occurs when the fetus dies and is expelled from the body after the twentieth week of pregnancy.

Complications

Premature birth- Delivery before 37 weeks. The baby is not fully developed and complications can arise.

Low birth weight- Some are premature while others just have not grown enough before birth. Can reduce the chance of this happening by practicing healthy habits during pregnancy.

Identical twins- Develops from a single fertilized egg. Embryo divides into two separate embryos.

Fraternal Twins- Two eggs are fertilized by two sperm. Can be different sex.

Multiple Births